The present invention relates in general to a safety system for airports and airfields, and more particularly to a synthetic turf system for enhancing runway and taxiway markings.
Airfields, including military airfields, small airfields and large commercial airports presently have grass surfaces adjacent to the airport runways and taxiways. These natural grass surfaces are difficult, time consuming and expensive to maintain and are not aesthetically pleasing. More importantly, the existing grass surfaces create potential safety problems for departing and arriving aircraft. The existing grass surfaces also create potential safety problems relating to the clean-up of hazardous waste spills and to the use of pesticides and herbicides necessary for proper upkeep of the grass.
One further problem with natural grass surfaces at airports or airfields is improper water drainage. In typical natural grass installations, the surface of the soil is approximately at the same height as the concrete (or other) surface of a runway or taxiway. The height of the grass thus normally extends past the height of the runway or taxiway surface. Grass clippings, dust, dirt and debris blown across the runway or taxiway, catch the overextending lip of grass and collect adjacent thereto, creating a more extensive vertical barrier. The clippings, dust, dirt and debris trapped adjacent to the runway or taxiway increase the potential of xe2x80x9cforeign object damagexe2x80x9d or xe2x80x9cFODxe2x80x9d to airplanes and are therefore classified as xe2x80x9cFODS.xe2x80x9d FODS are any foreign object that can damage a stationary or moving aircraft, specifically including a turbine engine.
The collected clippings, dust, dirt and debris along the edge of the runway or taxiway also inhibit proper water drainage from runways or taxiways. This build-up also traps and pools rainwater that contacts the runway or taxiway and drains to their sides (i.e., down their grade). The water eventually drains into and through the build-up and often creates a three to four foot (30 to 40 cm) area of wet mud adjacent to the runway. The grass in this area often dies, the mud dries and the top soil erodes so that new grass seed cannot effectively form a root system. Grass sod directly adjacent to a runway or taxiway can become loose, fly up and become a FOD, so that airports are effectively stuck with eroded soil in safety areas adjacent runways or taxiways.
Commercial airports (and certain other airports) must include graded surfaces adjacent to airport runways and taxiways capable of handling a hundred year flood. A conventional grade for such surfaces is a drop in height of at least one quarter inch (0.62 cm) for every foot (30 cm) in a direction perpendicular to the runway, or approximately a two percent drop. Over time, the flow of water carrying dirt and debris away from the runway or taxiway erodes the grade, at least at certain points, in the natural grass surfaces adjacent to the runway or taxiway. Water tends to pool in such areas of the natural grass where the grade is eroded. The pooled water also kills the grass and creates muddy areas where little grows. The muddy areas are aesthetically displeasing and conventional vehicles such as sanitation trucks, maintenance trucks and emergency vehicles cannot travel on or over the muddy areas, if necessary.
In dry, desert like climates, sand adjacent to runways and taxiways also creates problems. Little grows in sand, which leaves the airport with the unenviable choice of either planting, irrigating and maintaining an expansive and expensive natural grass surface or exposing large areas of aesthetically displeasing sand. Conventional vehicles such as sanitation trucks, maintenance trucks and emergency vehicles also cannot travel on or over the areas having sand, if necessary. Windblown sand can also be a dangerous FOD, which in certain instances has been known to sand blast the inside of a jet""s turbine engine.
As mentioned above, both wet and dry climates in combination with natural grass adjacent to airport runways and taxiways create potential safety problems; namely, through the creation of FODS and by potentially limiting access to and from the runway or taxiway. Natural grass is also expensive to upkeep. In peak periods, some airport operators must mow twice a week. Weeds, high grass, muddy areas and other obstructions collect litter and debris intermittently over the entire airport or airfield. For example, Los Angeles international Airport currently maintains full time employees whose primary responsibility is to collect litter and trash from the runways and taxiways and adjacent safety areas.
Although airfields are noisy and frequented by large, fast moving jet-powered aircraft, they still tend to support wildlife. Airfields often cover large expanses of open natural grass field surrounded by fences, providing good visibility and a haven for birds and other animals from man and pets. Man-made retention basins and drainage ditches provide a convenient source of free standing water. Mowing machines leave behind mowed straw and the like for nest construction and shattered seeds and maimed insects for food.
Another well known and potentially dangerous safety problem furthered by natural grass are birds and other animals. Many birds including gulls, waterfowl, raptors such as hawks and other species flock to airfields to eat, drink and reproduce. Birds eat insects and grubs which live in natural grass up to six inches (15 cm) below the soil surface. Birds also eat rodents, which feed on the insects. Standing water, especially after fresh rains, attracts many species of birds, including waterfowl. Large birds such as ducks or geese also create especially dangerous conditions for aircraft and are classified as FODs. Natural grass further provides materials and cover for birds to nest and breed.
Many airports and airfields report collisions between airplanes and birds and other animals that have the potential to damage an airplane. In July 1998, a Boeing 757 struck a hawk while ascending from Dallas Fort Worth airport. The plane ingested the bird into its left engine, tower personnel reported flames coming out of the engine and the plane landed safely. In May 1998, a Boeing 767 struck two Canadian Snow Geese while departing John F. Kennedy International Airport. The plane landed immediately with a damaged No. 2 engine and a hole in the right flap. In the same month, a Boeing 727 struck Canadian Snow Geese while ascending from Colorado Springs Metro Airport destroying one engine, cracking the plane""s radome and causing $1.4 million in damage to the plane. Also in the same month, an F-16 struck white pelicans near Ainsworth, Nebr., which penetrated a windscreen and caused the pilot to eject.
In April 1998, an MD-80 struck geese ascending from La Guardia airport in New York. The geese destroyed the plane""s radome. The plane had airspeed problems and had to divert to and land at Newark airport. In the same month, a Boeing 737 struck a bird while ascending from Dane County Wisconsin Regional airport, damaging an engine and causing a precautionary landing. In March 1998, a Boeing 727 struck a bird on takeoff causing major engine damage and a runway to be closed to remove engine fan blades. In the same month, a Merlin 4 struck a bird on approach to Denver International, the pilot took glass to the face but landed safety. In February 1998, a Cessna Citation flew through a flock of gulls in Watsonville, Calif., which damaged its fuselage windows, an engine and several wing panels.
In January of 1998, a bird struck a Boeing 737 while leaving Salt Lake City International and damaged the plane""s No. 1 engine. In that same month, snow geese forced the emergency landing of a Boeing 727, damaged an engine, tore the radome and pilot tube from the aircraft and damaged both leading edges of the airplane""s wings. Also in that same month, a Cessna Citation hit a deer during rollout at Horse Shoe Bay Airport in Texas, puncturing a fuel tank and spilling 200 gallons of fuel. In September of 1995, a bird air strike caused the crash of an E-3 AWACS aircraft at Elmendorf AFB, Ala. In June 1995, a Concorde on final approach to John F. Kennedy International airport struck several geese, which destroyed two engines.
The problems created by birds are exacerbated by the variety of birds. Often times eliminating one target species welcomes the arrival of another. For example, allowing grass to grow longer to discourage waterfowl promotes the rodent population, which in turn promotes the population of rodent eating birds. Known Bird Aircraft Strike Hazard plans, known as xe2x80x9cBASHxe2x80x9d plans, are trade-off creating methods that require constant adjustment. For example, airports can have a problem with gulls during winter months and smaller flocking birds in the summer months. If an airport produces known bird distress calls in its BASH program, the airport may have to produce gull distress calls in the winter and, for example, blackbird distress calls in the summer.
Birds are not the only species hazardous to airplanes and airports or airfields. Deer, usually in excess of one hundred pounds, and usually active after dark, can cause substantial damage and create potentially dangerous situations for pilots. Planes have been known to hit coyotes, which are attracted to areas having a large rodent population. Woodchucks and prairie dogs gnaw through underground wiring. Beavers can dam drainage ditches and flood airfields. An abundance of worms or other grubs on a runway, especially after a heavy rain, can also create a dangerous situation for planes taking off and landing.
Known animal, pest and BASH programs are either expensive, time consuming or illegal and in most instances do not solve all of the problems. One known solution is to employ a propane cannon. As stated above, airfields are already noisy, so that birds and other wildlife become accustomed to loud noises. Propane cannons also require active management. Live ammunition in combination with propane cannons is more effective, but live ammunition may not be legal, requires active management and is inherently dangerous.
Pyrotechnics (i.e., industrial or agricultural fireworks including shellcrakers, bird bombs and screamer sirens) are relatively effective and have been authorized for purchase by the United States Air Force. Such techniques, however, require active management including proper placement. They are generally not audibly pleasing to humans and do not provide an acceptable solution for unknowing passengers taking off or landing in a commercial jet.
U.S. Pat. No. 5,986,551, entitled xe2x80x9cMethod and System for Preservation Against Pesky Birds and Pest Animalsxe2x80x9d, issued on Nov. 16, 1999. The patent generally discloses a method and system for eliminating birds. The disclosure employs rotating-hunters and falcon imitators and requires sequentially, actively agitating the hunters or falcon imitators, removing all nests from an area that a system user desires to purge, and actively agitating the hunters or falcon imitators again. This is followed by a lessened, intermittent and protracted agitation.
Known hazing techniques such as loud noises and moving scarecrow type figures may provide a temporary solution. Hazing techniques at best only temporarily move birds and animals from one part of the airport to another, whereby the birds soon become habituated to the hazing and return. Each of the hazing systems requires active management, including proper placement and adjustment and has the drawback that whatever apparatus is in place to scare the birds or animals may also scare consumer airline passengers.
Runway incursions present another significant safety problem for airports and airfields. The Federal Aviation Administration (xe2x80x9cFAAxe2x80x9d) defines a xe2x80x9crunway incursionxe2x80x9d as, xe2x80x9cany occurrence at an airport involving an aircraft, vehicle, person, or object on the ground that creates a collision hazard or results in loss of separation with an aircraft taking off or intending to take off, landing, or intending to land.xe2x80x9d A xe2x80x9ccollision hazardxe2x80x9d is defined as any xe2x80x9ccondition, event or circumstance which could induce an occurrence of a condition or surface accident or incident (e.g., a pilot takes an unplanned or evasive action to avoid an aircraft, vehicle, object, or person on the runway).xe2x80x9d xe2x80x9cLoss of separationxe2x80x9d includes xe2x80x9can occurrence or operation, which results in less than the prescribed separation between aircraft, vehicles, or objects.xe2x80x9d For definitions, see:
http: //www.faa.gov/runwaysafety/, under statistics and data.
The FAA places runway incursions into three general causal categories, namely: (i) a pilot can cause a pilot deviation (xe2x80x9cPDxe2x80x9d); (ii) a tower controller can cause an operational error (xe2x80x9cOExe2x80x9d) runway incursion; and (iii) a person or vehicle on a runway or taxiway can cause a vehicle/pedestrian device (xe2x80x9cV/PDxe2x80x9d) runway incursion. Calendar year 2000 also had one miscellaneous incursion. The total number of runway incursions has steadily risen from 187 in year 1988 to 429 in the year 2000. The proportion of PD related incursions has also risen from 68 out of 187 in 1988 to 256 out of 429 in the year 2000.
Runway incursions have led to serious accidents. In 1994, a DC-9 collided with a Cessna 441 upon departure. The Cessna 411 mistakenly taxied past its assigned runway and onto the DC-9""s runway. The tower controller cleared the DC-9 for take-off. The DC-9 impacted the Cessna 411 upon taking off. Recent serious runway incursions, such as one near collision of two 747 jumbo jets at Chicago""s O""Hare International airport on Apr. 1, 1999, led the U.S. National Transportation and Safety Board (xe2x80x9cNTSBxe2x80x9d) to issue new air traffic safety procedures.
Skeptical that any technological solution will soon solve the increasing occurrences of runway incursions, the NTSB recommends that pilots be told to stop before crossing any active runway and wait until an air traffic controller gives permission to cross. The NTSB recommends that pilots wait for specific clearances rather than rely on implied clearances and that 14 Code of Federal Regulations (xe2x80x9cCFRxe2x80x9d) Section 91,129(i) be amended to reflect these changes.
The Aircraft Owners and Pilots Association (xe2x80x9cAOPAxe2x80x9d) stresses that pilot education and information are the key to reducing runway incursions. One cause of the problem is that the complex instrument panels in many airplanes cause pilots to be xe2x80x9cheads downxe2x80x9d for substantial periods of time. When a pilot is xe2x80x9cheads down,xe2x80x9d it is more difficult for the pilot to know the plane""s exact position on the runway or taxiway. One of the easiest and most effective solutions to the increasing problem of runway incursions is to educate pilots on the airport layout. Pilots should be able to taxi to and from an active runway without getting lost. Moreover, when pilots do look out their windows, airport markings should be clean and legible.
Presently, the pavement markings and small upright runway signs placed near runways and taxiways provide limited guidance to pilots, ground crews and tower controllers. The pavement signs fade and chip and do not contrast well against gray pavement. The upright signs are necessarily small, so that pilots, grounds people and tower personnel can have an uninterrupted view of other ground and air vehicles on intersecting and adjacent runways and taxiways.
One possible solution to the problem of runway incursions is to chalk or paint airport markings onto natural grass. However, simply chalking or painting natural grass with airport markings does not provide a viable solution. Mowing natural grass having an airport marking obviously damages or destroys the marking. The marking would likely have to be repainted on a regular basis. Painting natural grass also likely hurts or destroys the grass, requiring new sod, or requiring that the marking be painted onto a different and unfamiliar area of natural grass.
One proposed solution for marking natural grass is disclosed in U.S. Pat. No. 6,048,282 entitled xe2x80x9cLine System for Playing Field,xe2x80x9d which issued issue on Apr. 11, 2000. This reference discloses a system for visually marking a line in a natural grass playing field. The system enables the marking of a permanent line for sports played on natural grass, e.g., to mark out the perimeters of the play area and various boundaries of the game. The system involves cutting a trench in a natural grass surface, laying a suitable strip of synthetic grass having side flaps laterally extending from either side of the strip and anchoring the strip by installing natural grass onto the side flaps, wherein the natural grass also abuts the artificial turf strip.
For many reasons, this sports related system does not provide a workable solution for airport safety applications. This apparatus and method does not provide a workable solution for installing elongated dashed lines, multiple parallel lines or airport markings having rounded edges or complex shapes. Also, a strip or patch of artificial turf between sections of natural grass does not provide enough synthetic surface to accomplish the safety features discussed below. Further, natural grass is not compatible with the subsurface or base as described below.
Accordingly, there is no known solution for providing permanent airport markings on the surface of areas around airport runways and taxiways. A number of references teach machines and apparatuses for making artificial or synthetic turf. However, the hallmark use for synthetic turf has been for sporting events such as football, rugby, soccer, golf, field hockey and baseball. These sports primarily make use of the synthetic turf""s resiliency in the face of repeated severe shearing forces and of the turfs relatively low maintenance requirements. Synthetic turf also facilitates indoor stadiums and practice facilities that shield players and fans from harsh ambient conditions. The turf has likewise been adapted for these uses.
For example, U.S. Pat. No. 4,337,283 entitled xe2x80x9cSynthetic Turf Playing Surface With Resilient Top-Dressing,xe2x80x9d issued on Jun. 29, 1982 and discloses a playing surface for athletic games. Referring now to FIG. 1, this patent describes a section of turf used for sporting applications. The sports turf system 10 includes a base 12 that establishes the contour of the playing surface. The base 12 consists of concrete or asphalt pavement, compacted clay and gravel rolled into ordinary dirt. Although not shown, a slight slope or grade in the base 12 is preferable to facilitate surface water drainage.
Sports applications employing synthetic turf 14 have included a moisture barrier 16, such as a polyethylene sheet between 2 and 10 mils thick suitably adhered to the base 12. This reduces water penetration and protects the base from substantial ground moisture. Sport applications typically employ a turf 14 that includes a tufted or knitted pile fabric backing 18, such as woven polypropylene. A multi-filament or fribulated yarn 20 made from, e.g., xe2x85x9c inch (0.93 cm) wide polypropylene ribbon five mils thick, which is slit and twisted to form a plurality of thin filaments or synthetic grass blades 22, is tufted or stitched through the fabric backing. If the yarn 20 is fribulated, the thin filaments 22 remain connected at certain points so that the yarn when stretched apart creates a honeycombed mesh. Known strands of yarn 20 can comprise from twenty to fifty or more individual filaments 22.
Typical tufts or stitches include three to eight multi-filament yarns 20 per inch (2.5 cm) on conventional carpet tufting or stitching machines. The height of the yarn filaments 22 (i.e., grass blades) can vary but is typically between xc2xd inch to 2 inches (1.25 to 5 cm) high. The machines typically produce rows of tufts that are commonly xe2x85x9c inch to xc2xe inch (0.93 to 1.87 cm) apart.
Tufting or stitching different types of yarns into a standard carpet by threading different yarns into a plurality of laterally aligned needles is well known. For example, in a high-low technique, the carpet machine at predetermined times is fed shorter yarns to produce a shorter pile height. Taller pile heights of a different yarn, adjacent to the shorter pile heights, cover the shorter pile heights. The machines and methods for performing the high-low technique are disclosed in U.S. Pat. Nos. 3,016,029, 3,067,701, 3,272,163, 3,433,188, 3,435,787 and 4,216,735.
Other machines select different yarns according to a predetermined pattern. The pattern driven machines are disclosed in U.S. Pat. Nos. 3,056,364, 3,117,833 and 3,547,058. One carpet machine specifically adapted to tuft complex designs into carpets is disclosed in U.S. Pat. No. 5,392,723. It should be understood that while these patents teach methods and apparatuses for tufting or stitching various patterns into a carpet, none of these patents disclose or suggest a machine or method for making artificial turf. None of these references address airports, airport safety or runway incursions.
The underside of the pile fabric backing 18 can be coated with a resinous coating 24 that secures the tufts in place. The coating 24 increases the dimensional stability of the backing 18 as well as the moisture resistance of the backing 18. A preferred manner of coating the backing 18 is to contact the back of the pile fabric with a solution of vinyl polymer in a volatile, non-aqueous solvent and then subject the pile fabric to a heat treatment to evaporate the solvent and cure the vinyl polymer coating. Conventional polyvinyl chloride, polyvinyl acetate or natural or synthetic rubber latex coatings can be employed. The resinous coating 24 is sometimes referred to as a secondary backing and can also be considered a moisture barrier. In sport applications, it may then be possible to omit the moisture barrier 16 if the pile fabric backing 18 is provided with a suitable resinous coating 24.
In sports applications, after laying and adhering the synthetic turf 14 to the base 12, turf installers typically infill or infuse a layer 26 of compacted material having a mixture of resilient particles and fine sand between the synthetic grass blades. Turf installers have been known to use a variety of different resilient materials, such as: (i) granulated cork; (ii) rubber particles including natural rubber or synthetic rubber; (iii) beads of synthetic polymers such as vinyl chloride, vinyl ethers, vinyl acetate, acrylates and methacrylates, polyvinylidene chloride, urethanes, polyamids and polyesters; (iv) synthetic polymer foam particles; (v) vinyl foams such as polyvinyl chloride foams, polyvinyl ether foams, foamed polystryene, foamed polyurethanes and foamed polyesters; and (vi) foamed natural rubber.
Turf installers often utilize or mix two or more of the above mentioned resilient materials and can also add plasticizers, antioxidants and antistatic agents. Turf installers also preferably add fine sand to the infill to fill the interstices between the resilient particles to thereby form a more densely compacted infill layer 26. In sports applications, the sand is generally smaller in size than 30 U.S. screen mesh size and is preferably between about 40 and 200 U.S. screen mesh size. Fine sand also feels less abrasive to players when they contact the turf 14.
In typical sports applications, the turf installer provides an infill layer 26 from about fifty percent of the height of the synthetic grass blades 22 to substantially even with the top of the synthetic blades. In sports applications, turf installers typically prefer a projection of a synthetic blade between xe2x85x9 inch and xe2x85x9c inch (0.31 and 0.93 cm) above the infill layer. Turf installers maintain an infill layer 26 substantially to the top of the synthetic blades 22 to prevent a playing surface from having a noticeable grain. Normally, the synthetic grass blades 22 have a characteristic grain (i.e., a tendency to lay in a given direction related to the direction in which the material passed through the production machinery). The infill layer 26 counteracts this tendency and prevents the playing surface from having an easily noticeable grain.
A relatively high infill layer 26 that includes resilient materials also absorbs much of the shock of an object impacting the playing surface and improves the footing of a player running or walking across the surface, particularly when making cuts or sharp turns. The non-abrasive character of the infill and the controlled and diminished synthetic blade height projecting above the infill make a playing surface much less likely to produce rug burns or abrasions when players contact the surface.
To look like grass, the polypropylene yarn is died green. While synthetic turf has made use of a green dye, other applications of polypropylene employ different colors. Certain references therefore disclose dyes and methods for dying polypropylene. In the early 1990""s, Lyondell Petrochemical Company developed an enhanced dyeable polypropylene disclosed in U.S. Pat. Nos. 5,468,259, 5,550,192 and 5,576,366, which is marketed under the KROMALON(trademark) mark. Similarly, U.S. Pat. No. 6,039,767, assigned on its face to Equistar Chemicals, LP, entitled xe2x80x9cBlended Dyes and Processes for Dyeing Polypropylene Fiber,xe2x80x9d discloses an improved method of dyeing polypropylene and dyes therefore.
U.S. Pat. No. 6,039,767, assigned on its face to Eastman Chemical Co., entitled xe2x80x9cFluorescent Pigment Concentrates,xe2x80x9d discloses a fluorescent die suitable for coloring plastics. U.S. Pat. No. 5,206,058, assigned on its face to Eastman Kodak Company, entitled Process for Painting Polypropylene, discloses a plurality of methods for painting polypropylene, which include: (i) using an adhesion promoting composition as a separate primer coating between polyolefin (polypropylene) substrate and the paint; and (ii) using an adhesion promoting composition as an additive to the paint. It should be appreciated that these references do not disclose or suggest using dyes or paint for artificial turf, do not mention airports and do not address airport safety.
One aspect of the present invention involves an artificial turf system for areas, and primarily safety areas, adjacent to airport and airfield runways and taxiways. This system includes an aesthetically pleasing artificial turf that repels birds and other animals and an accompanying sub-surface, which enhances water drainage and facilitates the accessibility of airport vehicles to all parts of the runway or taxiway. The present invention preferably replaces existing natural grass as well as an application specific volume of soil or other material beneath the natural grass in target areas adjacent to and around airport runways and taxiways.
The present invention also applies to new airport or airfield installations, wherein the system employs an existing graded and/or compacted surface without additional excavation and/or compaction or natural grass replacement. The present invention uses an application specific form of known artificial turf, which includes plastic, such as polypropylene or polyethylene, or otherwise synthetic fibers slit or fribulated to appear grass-like. One embodiment of the present invention employs an application specific artificial turf, which includes the artificial or synthetic fibers and stiff fibers or repelling fibers otherwise uncomfortable for certain species to contact, walk on or lay on.
Beneath the artificial or synthetic turf, the present invention includes a sub-surface having an animal and plant retarding base, such as rock, crushed rock or concrete. The rock is preferably compacted to eliminate as much air as possible from between the rocks, to create a hard and stable surface. The base is thus able to support the weight of an aircraft or airplane. That is, the base at least supports the weight of small aircraft in small airfield applications and preferably supports the weight of any large aircraft or airplane in commercial or military airport applications. In this application, xe2x80x9caircraftxe2x80x9d and xe2x80x9cairplanexe2x80x9d are used interchangeably. Both terms include all aircraft and all airplanes.
By removing the top soil and natural grass and replacing them with compacted rock and artificial or synthetic turf, the present invention substantially limits the plant and animal life that can or desires to exist in the target areas. The present invention virtually eliminates grubs or insects that live on the surface or below the surface to a depth of approximately six inches (15 cm). The lack of natural grass, grubs or insects virtually eliminates rodents and other small animals that live in the natural grass and eat the grubs and insects. The lack of natural grass, grubs, insects, rodents and other small animals virtually eliminates all food sources for birds, which provide the greatest potential danger to aircraft. The present invention likewise eliminates virtually all food sources for other animals including deer, coyotes, etc.
The lack of natural grass, the ability to grow natural grass and the need to mow natural grass, which creates clippings convenient for nesting purposes, eliminates the cover and materials necessary for birds and other animals to nest and/or reproduce. The lack of natural grass also reduces the amount of environmentally unfriendly herbicides or pesticides that airport or airfield operators have to apply.
The present invention further includes a plurality of water drainage mechanisms to produce a target area near airport and airfield runways or taxiways substantially free from standing water or wet areas. Specifically, the present invention provides a layer of infill, which is primarily sand, between the synthetic fibers, that sufficiently absorbs water and provides a first line of defense against standing water. For heavy rains, the present invention enables water to drain through the artificial turf of the present invention into a sub-surface retention area. The system includes additionally grading the soil surface, creating the positive drainage necessary to eliminate standing water. The sub-surface of the present invention includes water sheeting layers or mechanisms, such as a waterproof membrane, to enable water to drain across the top of the turf leading into pipes or larger drains.
Removing standing water eliminates muddy or dead areas that currently proliferate at airports, resulting in a uniform, year round surface. The lack of available water eliminates another attraction for birds and other animals. A substantially dry surface in combination with a stable, compacted base also enables any type of airport vehicle to reach any part of the runway or taxiway at any time of the year, if necessary, subject only to extraneous conditions. The lack of mud around standing water reduces the likelihood of mud reaching the runway or taxiway and becoming a FOD.
The present invention further preferably includes installing the artificial turf, so that the grass tips of the turf are substantially even with or below the surface of the runway or taxiway, and so that grass clippings (from areas not employing the present invention), dust, dirt and debris can blow across the runway or taxiway unimpeded by undesirable obstructions as a result of grass growing above their surfaces. Such debris can blow all the way to an airport fence, unimpeded by weeds or mud, which facilitates easier and more cost effective waste removal. The transition or distance from the runway or taxiway surface to the top surface of the synthetic turf backing also enables a positive water drainage from the runway or taxiway to the turf.
The artificial turf of the present invention requires less maintenance, i.e., an occasional vacuuming of airborne soil and other materials that has collected on the turf of the present invention, which can lead to a limited germination of seeds. The turf may also require limited spraying of herbicides or pesticides if weeds begin to grow. The turf of the present invention preferably includes polypropylene fibers representing grass blades, a woven polypropylene backing into which the fibers are woven, a polyurethane backing and a pure sand infill. Each of these materials absorb hazardous material spills, such as jet fuel, and are readily replaceable without exposing large areas of bare dirt near a runway or taxiway. Each of these materials also retards and reduces a fire, such as that related to a fuel spill or other incident.
Another aspect of the present invention involves a system for areas near the ends of airport runways which includes an aesthetically pleasing artificial turf that covers and forms part of a soft ground arrester bed for slowing the motion of a runaway aircraft. The arrester bed system includes all the drainage features, aesthetics, ease of maintenance and accessibility of the artificial turf system described above.
The arrester bed system employs a deeper base than the artificial turf system, and the base of the arrester bed system preferably includes rolled rather than crushed rock, to soften the shock of an impacting plane and to absorb its kinetic energy. The arrester bed system also includes a turf area extending from the end of the runway a sufficient distance, preferably, on the order of a thousand feet (300 m), while the artificial turf system provides substantial benefits at sufficient distances, on the order of one hundred to two hundred feet (30 to 60 m).
A further aspect of the present invention is to provide a turf that inhibits or repels loitering animals. As illustrated above, the present invention eliminates the attractions for animals including birds to congregate on the artificial turf of the present invention, including eliminating food, water and cover and materials for reproduction. However, certain species, namely seagulls, tend to loiter in areas for no apparent reason. To counteract such loitering, the present invention contemplates using artificial turf having stiff or repelling fibers among the polypropylene fibers, which are uncomfortable to touch, stand on or lay on. The present invention contemplates that the stiff or repelling fibers bother the web-footed seagull as well as animals having paws or hoofs.
Yet another aspect of the present invention includes providing at least one segment, area or portion of a multicolored or multi-pigmented synthetic turf adjacent to or near airport runways and taxiways. The multicolored turf segments or areas provide a permanent, readily implemented and effective way of communicating with pilots, ground crews, tower controllers and airline passengers. The multicolored or multi-pigmented turf areas provide an effective tool for decreasing the frequency of runway and taxiway incursions.
The multi-pigmented turf segments include a plurality of differently colored dyed or painted fibers, including fluorescent fibers, which are tufted or stitched into the artificial turf. The multi-colored turf segments also include one or more sections of a differently colored turf section that is cut out and stitched together with a section of a base colored turf, e.g. green. The multicolored turf segments also include placing a stencil over the base colored turf and painting the base turf with one or more colors, in a desired shape or pattern, using suitable paints.
The airport marking system of the present invention includes an artificial turf segment having a backing with base colored fibers and marking fibers securely installed in an airport, wherein the marking fibers define an airport marking. One airport marking of the present invention is adapted to inform a pilot to hold a position before a runway or taxiway. Another marking is adapted to direct a pilot where to move an airplane. A further marking is adapted to inform a pilot of an airplane""s current position in the airport. Other airport markings are adapted to define an end of a runway or taxiway. A further airport marking is adapted to define a hazardous parking area. The airport markings therefore include, among others, one or more: (i) runway holding position lines; (ii) taxiway holding position lines; (iii) instrument landing system boundary markings; (iv) holding position signals; (v) direction signals; and (vi) location signals.
The airport marking system of the present invention includes a multicolored artificial turf segment having a backing with base fibers and marking fibers, wherein the marking fibers are visually different than the base fibers. The marking fibers have various colors adaptable to define a plurality of different shapes and patterns. The marking fibers of the present invention define: (i) one or more characters including numbers and letters; (ii) a character having a border around it; (iii) a plurality of parallel lines; (iv) a dashed line; (v) a plurality of parallel lines and a plurality of intersecting lines perpendicular to the parallel lines; (vi) a plurality of chevrons; (vii) a plurality of parallel lines disposed at an angle relative to a side of the segment; (viii) a plurality of checkered four sided shapes; (ix) one or more arrows; (x) an arrow adjacent to a character; and (xi) combinations thereof.
The multicolored or multi-pigmented turf segments are adaptable to be included in the different safety systems disclosed herein. Namely, one multicolored system includes a base adapted to support the weight of an aircraft and a soil surface beneath the base. An arrester bed system of the present invention includes a multicolored artificial turf segment securely installed in an area of an airport; a base beneath the turf segment, the base adapted to slow a moving aircraft; and a soil surface beneath the base. A multicolored or multi-pigmented artificial turf for repelling animals or birds includes a backing; a plurality of repelling fibers attached to the backing; a plurality of grass-like base fibers attached to the backing; and a plurality of grass-like marking fibers attached to the backing having a second color.
It is therefore an advantage of the present invention to provide an artificial turf system for airports and airfields that retards birds and other animals and has a sub-surface that enhances water drainage and as well as the accessibility of airport vehicles.
Another advantage of the present invention is to provide an artificial turf system for airports and airfields that includes an artificial turf surface and a sub-surface that slows a moving aircraft.
A further advantage of the present invention is to provide an artificial turf adapted to retard or repel loitering animals.
Yet another advantage of the present invention is to provide a multi-pigmented turf which visually defines airport markings, symbols, messages and the like.
Other objects, features and advantages of the invention will be apparent from the following detailed disclosure, taken in conjunction with the accompanying sheets of drawings, wherein like numerals refer to like parts, elements, components, steps and processes.